A boat lift is a mechanism for lifting a boat at least partially out of the water and for securing the boat at a desired location, such as next to a dock. A boat lift mechanism may include a winch.
A winch is a mechanism that winds up or winds out a cable or tether or rope or wire to draw in or draw up or lift up or let out an object at the distal end of the cable. A winch may be hand powered, electric powered, hydraulically powered, pneumatically powered, powered by an internal combustion engine, or powered in some other fashion. A winch may include a mechanism to prevent reverse action of the winch (a winding out) and such a mechanism may be a ratchet and pawl, a solenoid brake, or a mechanical brake.
As indicated, a winch may be hand powered. These hand powered winches may have a hand wheel. Between the hand wheel and the winch, these hand powered winches may further have a winch shaft. When the hand wheel is removed from the winch shaft, an end of the winch shaft is exposed. The end of the winch shaft may include an exterior threaded portion and an interior threaded portion. The interior threaded portion may be a threaded opening that is coaxial with the exterior threaded portion and the winch shaft.
As further indicated, a winch may be electrically powered. For example, the Davis U.S. Pat. No. 6,767,004 issued Jul. 27, 2004 and entitled Replacement Motorized Drive Unit For Boat Lifts discloses a disc that drives a mating disc on the winch box shaft. The Gargaro, III et al. U.S. Pat. No. 7,784,767 issued Aug. 31, 2010 and entitled Boat Lift Drive discloses a drive shaft that includes an interior threaded opening that engages a threaded end of the winch shaft to directly connect the drive shaft to the winch shaft. The Hager U.S. Patent Application Publication No. US 2011/0049450 A1 published Mar. 3, 2011 and entitled Boat Lift Motor Having Spline Shaft discloses a worm gear reducer that rotates a tubular drive shaft having radial splines.